While May would normally be a month of continuing seasonal decline in new COVID infections, on the way to a mid-summer annual low, we reached this year’s sharp decline in late March and the number have been gradually but stubbornly but consistently rising every week since. 

As you can see in our composite chart, the overall Ontario COVID viral count as measured by municipal wastewater PCR test results has roughly doubled in that period. Actual human PCR test results have risen more sharply and COVID-related hospitalization have followed suit. ICU admission rates tend to lag hospitalizations by a couple of weeks but the most recently-published figure is also suggestive of an uptick.  

The more independent COVID-19 Resources Canada Hazard Index has not been updated over the past three weeks.  Its previous estimate of one in 76 Ontarians being COVID-infected and hence infectious may therefore underestimate the current number. 

The most recent US Centers for Disease Control estimates of circulating COVID variants summarized in this week’s composite chart are again all displayed in shades of blue, illustrating the utter dominance of the JN.1 family of variants, which now accounts for virtually all new cases. While incidence of the original JN.1 strain dropped by 80% over the past eight weeks, that’s because it has been severely outcompeted by its progeny. Of those, its KP.2 derivative continues to enjoy the largest single “market” share at 29% but is already at risk of being soon outcompeted by its KP.3 cousin, which has grown eight-fold in that same period. Previously in the pandemic, a single variant tended to quickly soar to dominance and then remain there for some months. The JN.1 family appears to be differentiating too quickly for any one variant to be truly dominant and to hold the top position for more than a few weeks.  The increased ability of each new strain to evade our waning immunity combined with our increasing neglect of simple precautionary measures may explain the current unseasonal rise in new cases.